The delivery of drugs through dry powder aerosols to the respiratory tract of the intended patient or test subject is a common way to ensure the transfer of the drug into the system of the patient or test subject.
A variety of inhaler systems and methods exist for delivering dry powder to the respiratory tract of patients and/or test subjects. Metered dose inhalers deliver a metered dose of powdered drugs through inhalers that compress a canister or puncture a capsule. In such embodiments, the patient or test subject must inhale deeply in order to receive the required amount of dry powder to treat their ailment. In order for the patient or test subject to receive such dosage, the patient or test subject must make a conscious effort to inhale deeply at the appropriate moment in which the dry powder aerosol is ready to be delivered. However, for certain patients and test subjects, the ability to inhale deeply at the appropriate moment is not always controllable. For example, when delivering aerosols to certain test animals, a researcher cannot coax the animal or communicate with the animal being tested to make it inhale at the correct moment. Therefore, when testing animals with dry powder inhalation drugs, a low efficiency of deposition of the drug within the animal's respiratory tract often occurs. A similar problem occurs when trying to coax children to inhale at the proper moment.
When testing animals, direct insufflations may be used to deposit the drugs within the respiratory tract of the animal. However, this approach requires anesthesia and can cause untoward health problems in the animals and is not feasible for chronic treatment.
A variety of nebulizers and methods for using nebulizers have been employed to deliver drugs to the respiratory tracts of test subjects and patients. Such nebulizers do not require special breathing patterns. Nebulizers create a mist that is delivered in proximity to the mouth and nose of the patient or test subject. Nebulizers, however, require the use of a large amount of the drug in liquid form. The amount necessary to deliver an effective dosage to the patient or test subject is much larger than the amount deposited within the respiratory tract of the patient. A large majority of the drug being tested escapes into the surrounding environment. Therefore, much of the drug is wasted during a dosage session using a nebulizer. When testing drugs on small animals, the use of a nebulizer can waste large amounts of the drug being tested. These drugs are often times very expensive and time-consuming to make. Also, with experimental drugs, only small amounts of the drug may be available at any given time. Therefore, it is preferred that such nebulizing systems not be used for experimental drugs to conserve the drug for test purposes.
Therefore, a need exists for an improved delivery system of dry powdered aerosol drugs to test subjects that cannot consciously inhale deeply upon command to facilitate proper delivery of the drugs within the respiratory tract of the patient or test subject.